1. Field of the Invention
The present invention relates to outlet protection apparatus for preventing debris from clogging the exposed end of suey, drainage or irrigation pipe, and for simultaneously preventing entry into the pipe of small animals such as beavers. The present invention specifically relates to elongated piping outlet protectors which permit accumulated debris to flush through and out the protector, while simultaneously preventing entry of small animals into the pipe.
2. Prior Art
Large-diameter piping is often used to direct the flow of rainwater under roads and away from lands sensitive to oversaturation by water such as agricultural fields. Typically such piping is buried in natural soil and terminates in one open end which directs water flow into a drainage ditch, reservoir, or natural stream. In some cases piping directs the flow of water under a roadway and includes two open ends, one on each side of the road.
This type of drainage piping is highly useful but suffers from two main drawbacks. First, during storms and other intense weather activity, large debris may be washed into the piping and may become jammed in the pipe. Second, the open end of drainage piping attracts water-seeking animals; some particularly industrious animals such as beavers commonly construct dams across one open end of the piping, blocking the piping, backing up water and thereby creating a pond on the other end.
To overcome these disadvantages several devices have been developed for preventing animals from gaining access to drain pipes while allowing water and debris to flow out of the drain. For example, U.S. Pat. No. 830,112 (Tenold) shows a drain tile and pipe protector for a pipe comprising a generally square end box fitted with a downwardly angled filter grate which is drilled with a plurality of small holes. The grate is mounted a hinge pin enabling the grate to be selectively raised or lowered.
A similar invention is provided in U.S. Pat. No. 928,481 (Tenold), which shows a more elaborate angled gate for the end of a pipe which includes an interior grate connected to a pivot arm and a movement arm. The gate may be raised or lowered from the exterior of the grate housing by moving the protruding end of lever.
U.S. Pat. No. 961,834 (Barlett) shows an animal guard for pipes consisting of two symmetrically identical doors each having a plurality of elongated vertical channels through which debris or water may flow. The doors are secured to a pipe end fitting using hinges. Further, the doors are prevented from moving inward by springs secured to the interior of the pipe using hooks.
The device in U.S. Pat. No. 3,289,840 (Kahn) prevents small animals from gaining access to drain pipes by providing a pivotable gate which remains closed and is manually cleaned to remove built up debris.
U.S. Pat. No. 4,356,087 (Miles) also shows a gate which is mounted within the open end of the drain pipe and remains in a closed position to prevent small animals from gaining access to the drain pipe. The flow of drain pipe water containing debris results in the gate pivoting open to allow the debris to flow out of the drain pipe.
U.S. Pat. No. 4,702,828 (Mehmert) improves on the previous patents by providing a plurality of rotatable prongs that are self cleaning. In addition, it includes a tamper proof guard which keeps more intelligent animals such as raccoons from opening the gate.
The prior art does not appear to completely solve the problems overcome by the present invention. For example, the two patents to Tenold include a movable, hinged door having plural small holes, but the holes are too small to allow large debris to pass through. Additionally, there is no indication that small animals, particularly intelligent animals such beavers, could not devise a way to force the doors of Tenold shut by piling debris against them.
The patent to Kahn shows a drainage pipe cover which could be fouled by large, elongated material such as sticks which become lodged perpendicular to the pipes which prevent animals from entering the Kahn device. The Kahn device is directed to preventing rodents from entering drain pipes, but is not designed to prevent animals such as beavers from piling debris against the device.
The Barlett device shares the disadvantage of Kahn in that the Barlett covers could be fouled by long materials such as sticks becoming horizontally lodged against the door, without providing sufficient force to open the doors. It is also possible that the doors of Barlett could become partially opened and stuck in the open position by the discharge of large amounts of bulk material. Further, since the doors of Barlett open only one way, beavers or similar animals could easily foul the device by piling debris against the doors and preventing them from moving outward.
The patents to Mehmert et al. and Miles represent more modern, complex applications of the same principles shown in the prior patents. Both Mehmert and Miles show rotatable spike-like devices which have sharp, outwardly-facing spikes to prevent animals from entering, but which rotate under water flow pressure to enable large debris to spin through the devices. However, it is quite conceivable that a beaver or similar animal could pile enough debris against the drain pipe and guard to render it useless. Further, the present invention is far more simple than the Mehmert et al. and Miles devices, and consequently shares an economic advantage over these patents.
Thus, the prior art appears deficient in not providing a drainage or irrigation pipe protection device which simultaneously prevents small animals from building dams in the device or entering the pipe, and yet simultaneously permits debris to flow through and out the device without clogging it. Accordingly, those skilled in the art would find useful an elongated pipe outlet protection apparatus overcoming the above advantages. Those skilled in the art would find particularly useful an elongated, ogive or cone-shaped front grate for a pipe which both prevents animals from entering the pipe and permits large debris such as sticks to pass through the grate unimpeded.